Browsing by Author "Melaku, Mulugeta"

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    Computer Anxiety and Perceived Causes of the Anxiety Among College Students in Dessie
    (Addis Ababa University, 2006-06) Melaku, Mulugeta; Wole, Darge (PhD)
    The purposes of this study were to examine levels of computer anxiety, to identifY the gender differences in computer anxiety, to explore the influence of experience on computer anxiety, and to indicate the p erceived causes of computer anxiety among college students. A questionnaire and an interview were administered to collect data. I04 Information and Communication Technology college students were involved in the study. Analysis of variance and percentage were empluyed to analyze the data . According to the results, there is considerable computer anxiety among Information and Commu nication Technology college students in Dessie. The results also indicated stalis /ically significant gender- and experience-differences in computer anxiety. The significant differences were in favor of male students and highly experienced students. Moreover, some of the perceived causes of computer anxiety were identified. Finally, practical implications of the results and recommendations are indicated. I
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    Dynamics of Coherently Driven Degenerate Three-Level Atom in open Cavity
    (Addis Ababa University, 2014-04) Melaku, Mulugeta; Kassahun, Fesseha (PhD)
    In this thesis, we study the quantum properties of the light generated by a coherently driven degenerate three-level atom in an open cavity coupled to a vacuum reservoir. The three-level atom available in the cavity is driven by coherent light from the bottom to the top level. We perform our analysis by putting the noise operators associated with the vacuum reservoir in normal order. Employing the master equation and the quantum Langevin equation we obtain the di erential equations of the atomic and cavity-mode operators. Using the steady-state solutions of the resulting equations, we determined the photon statistics, quadrature squeezing and the local mean photon number. It is observed that the mean photon number is greater when = 0 than when = 0:1. We nd, like the mean photon number, the variance of the photon number to be greater for = 0 than for = 0:1. Moreover, we have also established that the maximum quadrature squeezing of the light generated by the atom, to be 43.42 % for = 0 and 42.22 % for = 0:1 below the coherent-state level. Thus in the absence of spontaneous emission the mean, the variance and the quadrature squeezing of the cavity light is greater than in the presence of spontaneous emission. Finally, we have found that a large part of the total mean photon number is con ned in a relatively small frequency interval